Fluoride compounds are used in dentistry primarily for caries prevention. Commercially available toothpastes contain a wide variety of remineralization compounds. Their effectiveness depends on the delivery of free or soluble fluoride ions (F-). Apart from them, there are also non-fluoride remineralization systems exist. They are based on calcium and phosphate ions, which are added to toothpastes. The aim of this study was to determine the concentrations of fluoride ions in aqueous solutions of toothpastes and to compare them to the label amount of fluoride concentration. Six toothpastes were chosen for the study. They contained different fluoride compounds: sodium fluoride (NaF), amine fluoride, sodium monofluorophosphate, amine fluoride/stannous fluoride, calcium fluoride, sodium fluoride/casein phosphopeptide-amorphous calcium phosphate complex (CPP-ACP). Two samples were prepared from each of the toothpastes. A single gram of the toothpaste was measured using the analytical scale and then dissolved in redistilled water. Next, the amount of F- ion was determined by use of ion-selective electrode (ISO 19448:2018 standard). The measured concentrations of F- ions in toothpastes containing amine fluorides and sodium fluoride matched the label concentration. Calcium fluoride and sodium monofluorophosphate didn’t dissociate in redistilled water, therefore the measured concentrations were lower than the label amount of fluorides in toothpastes containing them. Those results correspond to the available literature data. The measured concentrations of F- ions in the toothpastes with NaF/CPP-ACP and stannous fluoride/amine fluoride didn’t match the label concentration. Fluoride ions from the toothpaste containing NaF and CPP-ACP complex, despite the product containing NaF, didn’t dissociate in an aqueous solution. That indicates ion interactions between sodium fluoride and CPP-ACP complex.